A procedure for determining wear or corrosion of machine parts by using radionuclides

A procedure is suggested for determining the degree of wear or corrosion of two working surfaces of a machine part or of different working surfaces of two machine parts, made from materials of the same or similar chemical composition. Each of the working surfaces is activated by charged particles of a different kind (deuterons and alpha particles or protons for instance). Together with the working surfaces, at least two foils made from material on the same basis as the working surfaces are activated. Their thickness must be lower than the calculated thickness of the activated layer on the working surface. Liquid standards and filter standards are prepared from the foils. During the measurement, activated samples of a liquid medium (lubricant for instance) are taken, or the activity of a filter insert is measured. Gamma spectra of the radionuclides formed are scanned by employing an NaI(Tl) scintillation counter interfaced to an at least 256-channel amplitude analyzer. The spectra must be unfolded, and the evaluation is based on a comparison with the spectra of the standards. The entire procedure is illustrated in detail on a wear analysis of valve lifters of a compression ignition engine. (P.A.)